According to the article, the girl never learned any of the local languages after being rediscovered.  Presumably when she was lost at the age of 9, she did know a language that she has subsequently lost.

Children who are prevented from using their native language due to relocation or as in this case isolation tend to lose their native language.  In cases of relocation they often replace their native language with the language of the culture into which they have moved.  In the cases of the feral children, the isolation means that they end up with no language at all.

We have to be cautious about generalizing from the experiences of feral children, though.  There is so much that is unknown in the cases of each of the children that there could easily be other variables at work other than just age of exposure or removable of exposure to the language: physical abuse, sickness, malnutrition, psychological trauma, etc.

Read more about language loss at Wikipedia.

Read the original article at the Telegraph.

A British woman has suddenly started speaking with a Chinese accent after suffering a severe migraine, she said in comments quoted by British media Tuesday…

For more on Foreign Accent Syndrome, see the Wikipedia article.